Wall consisting of tubes or the like for furnaces or other heating arrangements



Feb. 7, 1939.

o. BLoMQulsT 2,146,560

. U, WALL CONSlSTING OF TUBES OR THE LIKE FOR FURNACES OR OTHER HEATING ARRANGEMENTS Filed 0ct. 14, 1936 y 2 Sheets-Sheet l rFeb. 7, 1939. U C)- BLQMQLHST I 2,146,560

WALL CONSJST'ING OF TUBES OR THE LIKE FOR FURNACES OR OTHER HEATING ARRANGEMENTS Filed Oct. 14, 1936 2 Sheets-Sheet 2 221235 l lia/9.@

JAJAJA @MDMQJJ pf E WCWOW3` 9 w15 8f *ff 'M if ff '9 9 l u75a E All j@ EL# .9 TVA W F Vw WNV 7 3 5 QL y) Patented Feb. 7, 1939 PATENT OFFICE WALL CONSISTING OF TUBES OR THE LIKE FOR FURNACES OR OTHER HEATING AR- RANGEMENTS Uno Olof Blcmqust,

of a part to Thure teras, Sweden, Stockholm, Sweden Vasteras, Sweden, assignor Axel Ragnar Strand, Vasand Harry Fredrik Albihn,

Application October 14, 19.36, Serial No. 105,465

, In Sweden October 16, 1935 6 Claims.

The last years development in the steam boiler technique is distinguished, among other things,

by endeavours toward .a better utilization of the active material of the boilers than has been possible in boilers of older types, whereby so-called radiation boilers have been arrived at, with furnaces surrounded more or less completely by water-cooled steel walls. These .furnace walls are generally made from tubes which are connected in some way or other into the circulation system of the boiler. For 'constructional reasons, the tubes, however, cannot be placed too close to one another, but must be spaced a sufcient distance so that the requisite strength is obtained, among other things, inthe walls of the domes or the collecting Vessels to which the tubes are connected unless a great number of vtube boxes are employed. To the extent in which the furnace wall is not entirely constituted by heat absorbing fire surface, its capability of utilizing the radiant heat will be reduced. It has therel fore been attempted in various ways to make the whole wall heat-absorbing, inter alia by filling the intermediate spaces between the tubes with heatconducting material for transferring to the tubes the heat absorbed by such material. A method as hitherto known of filling the intermediate spaces between the tubes in the tube walls of the radiation furnaces is to weld metal onto the tubes, for instance so-called fin tubes. At high temperatures in the furnaces, certain disadvantages occur, however, inasmuch as the flat fins cannot be made-sufficiently wide, without becoming unduly heated in the outer edges,

whereby the edges are burned and the function of the fins is impaired. Also, cracks are apt to form in the edges of the iins, said cracks propagating inwardly to the tube wall, so that the latter may ultimately burst.

The present invention refers to an arrangement for the provision of preferably watercooled walls in furnaces or the like, particularly for steam generators (steam boilers) consisting of tubes which are in known manner connected at their ends to domes or other collecting vessels, the invention being principally characterized in that the intermediate spaces between the tubes, which are connected at their both ends directly to the collecting vessels, are lled, entirely or in part, by one or more tubular members substantially parallel to the tubes, said members being connected at their both ends to the tubes at points located outside the connecting places between the tubes and the collecting vessels. It

is of particular advantage to connect the tubular 'a downcomer 4 to the lower collecting vessel 5,

members, which in the following are termed side tubes, in parallel, as regards the flow, to an intermediate portion of the appertaining main tube. One or more side tubes may be arranged on the one or on both sides of a main tube.

The arrangement according to the invention is serviceable not only for the generation o-f steam, or other gas by the evaporation of water or other liquid, but also for other heating apparatus in which the heat-absorbing medium is constituted, for instance, by some gas, such as steam in a superheater or air in an air preheater.

The invention will be described more closely hereinbelow with reference to the accompanying drawings.

Fig, 1 shows a vertical section of a steam boiler provided with walls covered by tubes in accordance with the invention. Fig. 2 shows a wall portion according to Fig. 1 to a larger scale. Fig. 3 is a section on line III-III in Fig. 2. Fig. 4 is a section on line IV-IV in Fig. 2. Fig. 4a shows a modification to a larger scale. Figs. 5-8 illustrate, in the same manner as Fig. 2, various methods of connecting the side tubes to the main tubes. Figs. 9 and l0 show sections of other types of tubes.

The steam boiler shown in Fig, 1 is suited for oiland/or carbon'powder` firing, but obviously the invention is just as applicable to grate-fired steam boilers.

In Fig. l, the side walls of a suitable brickwork are designated by I and Ia respectively, the visible remote head wall being denoted by 2. 3 designates a steam dome which is connected through which extends in parallel to therwall I on the lower side of the latter. Arranged on the upper side of the wall la and parallel to the latter is an upper collecting vessel S. Arranged on the head wall 2 is a lower collecting vessel I and an upper collecting vessel 8. The other collecting vessels 5 and I are connected to the upper collecting vessels 6 and 8 respectively by means of tubes 9 forming an internal covering of the walls I, la, 2 of the furnace chamber. Tubes I0 extend from the collecting vessel 6, and tubes Il from the collecting vessel 8, to the steam space of the dome 3.

The tubes e covering the wall I have an extension 9a at the top, said extension running transversely over the furnace chamber to the collecting vessel S. The tubes covering the wall la have an extension 9b at the bottom, the said extension running transversely over the lower portion of the furnace chamber to the collecting vessel 5.

I2 designates nozzles for the introduction of oil and/or 'carbon dust as well as secondary air into the furnace chamber.

The tubes 9 are provided, at least at the portions located along the walls, with side tubes I3 arranged according to the invention.

From Fig. 2, which illustrates a portion of the tube covering for the wall 2 to a larger scale, it will be seen that the tubes 9 may be secured in a normal manner, for instance by rolling, in the collecting vessels 'I and 8. Each tube 9 is provided with one or more, in this case two, tubular members or side tubes I3 arranged along the tube, the side tubes being so dimensioned and located as to fill the intermediate spaces between the tubes 9 to a suitable extent. The side tubes open into the tube 9 in suitable places, preferably in the proximity of the connection of the tube 9 to the collection vessels 'I and 8, in such a manner that liquid flowing from the one collecting vessel l out into a certain tube 9 will now in parallel through both the tube 9 proper and its two side tubes I3. The portion of the uid passing through the side tubes is returned to tube 9 in the proximity of the second collecting vessel 8, and ows into the latter through the connection of the tube 9 thereto. In a wall made in this manner for a steam generator, the side tubes I3 are thus connected into the circulation system of the boiler. The side tubes IS may be altogether free from their tube 9, except at the connecting points, where they are connected, for instance by welding, with the tube d in apertures provided for this purpose in the walls of the tube Si, or the side tubes I3 may be attached to the tube 9, for instance by welding, at one or more points or along the whole of the tube 9, as appears at l in Fig. 4a.

In the embodiment disclosed in Fig. 5, the tubes 9 are provided with one side tube I3 only. According to Fig. 6, there are two side tubes I3 on each tube 9, but in difference from Fig. 2, both side tubes are arranged on the same side of the main tube. In the same manner, three or more side tubes may be arranged. If desired, these side tubes may be connected directly with each other.

In the embodiments above described, the side tubes I3 are connected, as regards the flow, in parallel to the portion of the main tube 9 located between the connecting points of the side tubes.

It is also possible to arrange a side tube l3nt, Fig. 7, in such a manner that it will communicate at the top with a tube S, and at the bottom with another adjacent tube 9. It is also possible in a similar manner to arrange two or more side tubes i3d between the tubes 9, as shown in Fig. 8.

The tubes 9 are always arranged at a sucient distance from each other, in order that the openings for their attachment in the collecting vessels 'e' and S respectively shall not be located too near one another, whereby they would weaken the walls of the collecting vessels.

In a reconstruction of an old boiler, no alteration whatever is required in the collecting vessels. The only thing required is that apertures be provided in the walls of the tubes 9 for the connection of the side tubes I3. In this case, it is more suitable to make the side tubes I3 of a smaller diameter than that of the main tubes 9, in order to permit the tubes to be located in the same plane. On the whole, it is always the most suitable to make the side tubes thinner than the tube 9, so that the latter need not be weakened too much by too large connecting openings in the walls.

The arrangement with side tubes above described znay also be used in tubes that are provided with iianges. In this case, the side tubes I3 are disposed in front of the flanges, so that the latter will be protected against direct heat radiation which is detrimental to the life thereof. The side tubes are disposed in such a manner, however, as not to prevent heat radiation to the main tubes 9. Such an arrangement 'is shown in Vsection through the tubes, in Fig. 9, in which the main tube is again denoted by 9. On both si-des'of the tube 9, flanges I5 are arranged in the manner illustrated in the gure. The position of the side tubes I 3 also appears from the drawing. The side tubes are not arranged diametrically opposite one another, but are located athwart in front of the iianges I5, so that the latter are protected as far as possible against direct heat radiation. Finally, Fig. l shows a tube provided 'with flanges I5, said tube being adapted to be arranged in a corner of the furnace. The adjacent tubes 9 are disposed in rows extending in the directions of the flanges I5.

In the examples illustrated, the collecting vessels are shown as being straight. They may of course just as well be made arcuate, which may be the case, for instance, if the furnace chamber is made round.

In the example according to Fig. 1, the tubes 9 arranged at the walls I and Ia. are provided with side tubes on the vertical portion only, while the tube portions 9a and 9b, respectively, extending transversely over the furnace have no side tubes. rThese portions 9a, 9h vmay also, however, be provided with side tubes, provided that all tube portions 9a are not located in the same plane so that the flow of the flue gases is prevented.

l. In furnace walls for steam generators, the combination of spaced main tubes, collecting vessels in communication with said tubes at both ends of the latter, longitudinal flanges on said tubes, and side tubes `extending alongside of the main tubes, athwart in front of said flanges, said side tubes being connected at their both ends to the main tubes at points located outside the connecting points between the main tubes and the collecting Vessels.

2. In furnace walls for steam generators, the combination of spaced main tubes, collecting vessels in communication with said main tubes at both ends of the latter, and side tubes in the spaces between said main tubes, said side tubes communicating with the main tubes and being mechanically connected to the main tubes along the whole of their length.

3. In furnace walls for steam generators, the combination of spaced main tubes, collecting vessels in communication with said main tubes at both ends of the latter, and side tubes inthe spaces between said main tubes, said `side tubes communicating with the main tubes and being mechanically connected to the main tubes along a portion of their length.

4. In furnace Walls for steam generators, the combination of spaced main tubes, collecting vessels, said main tubes extending between and communicating at both ends with said collecting vessels and being of `constant cross section areas and .having radial openings vbetween their connecting vpoints with fsaid collecting vessels, and

side tubes of smaller diameter than that oi the main tubes and placed in the spaces between the main tubes, said side tubes being directly connected at both ends thereof to the main tubes at said openings.

5. In furnace walls for steam generators, the combination of spaced main tubes, collecting vessels, said main tubes extending between and communicating at both ends with said collecting vessels and being of constant cross sectional areas and having pairs of opposite radial openings between their connecting points with said collecting vessels, and side tubes o smaller diameter than that of the main tubes and placed on two opposite sides of the main tubes, said side tubes being directly connected at both ends thereof to the main tubes at said openings.

6. In furnace walls for steam generators, the combination of spaced main tubes, collecting Vessels, said main tubes extending between and communicating at both ends with said collecting vessels and being of constant cross sectional areas and having pairs of opposite radial openings between their connecting points with said collecting vessels, and side tubes of smaller diameter than that of the main tubes and placed on two opposite sides of the main tubes, said side tubes being directly connected at both ends thereof to the main tubes at said openings the side tubes being connected in parallel to the intermediate portion of the respective main tubes.

UNO OLOF BLOMQUIST. 

